In choke valves the sliding sleeve has a port and is axially moved for more or less alignment with a surrounding housing port to control the pressure drop across the choke valve. Typically a hydraulic fluid metering device or a j-slot assembly is used to move the sliding sleeve axially in the surrounding housing to control the opening size. In some designs in the past the sliding sleeve and the housing are rotationally locked with a lug in an axial recess arrangement. However, when made in certain small sizes there may not be enough room to use such a rotational locking arrangement. Other alignment systems use an open slot in a j-slot that steps the sliding sleeve axially for opening and closing the valve. That design is illustrated in U.S. Pat. No. 7,367,393 in the form of alignment lug 64 aligning housing components for a choke valve. Alignment is important because the openings in the sliding sleeve and the housing need to be in the same plane as the sliding sleeve is axially moved to control the pressure drop across the choke when it is partially or fully open. There are times when the choke is between the full closed and full open positions and other procedures are conducted through the valve that can result in relative rotation between the sliding sleeve and the housing in the absence of a rotational lock.
Accordingly, the present invention addresses a situation where the configuration of the choke such as the requirements for a pressure rating on the housing or a drift dimension through the sliding sleeve dictate against the provision of the known solution of rotationally locking the sliding sleeve to the surrounding housing. Instead of the traditional rotational alignment solutions that are not practically available in some situations, the present invention provides an alignment ring having a repeating pattern profile to match a similar profile at an end of the sliding sleeve. Accordingly, regardless of the initial orientation of the matching patterns, advancing the patterns toward each other will always produce an axial alignment of the circumferentially spaced ports on the sleeve with circumferentially spaced openings in the surrounding housing for normal operations. The sliding sleeve is preferably directed to the closed choke position which is the position where the profiles engage. If there is initial misalignment then bringing the patterns together realigns the sliding sleeve and housing ports for subsequent normal operation. This is done without reduction of the sliding sleeve drift dimension. These and other aspect of the present invention will be more readily apparent from a review of the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be found in the appended claims.